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Felsenthal Artillery Protractor

Description

This clear plastic semicircular protractor is divided by tens and marked by hundreds from 100 to 3,100 mils and from 3,300 to 6,300 mils. Mils are units used in artillery and other military applications; 1,000 mils is equivalent to 56.25°. A pinhole is at the origin point. The bottom edge of the protractor is divided by hundreds and marked by five hundreds from 0 to 8,000 yards. A small vernier appears to the left of the scale, and the scale is labeled: 1/20,000.

The interior of the protractor has a semicircular opening with a groove parallel to the origin point. Below the opening is a maker's mark: 16 INCH (/) G. FELSENTHAL & SONS, INC. (/) -CHICAGO-. The letters U.S. are printed above the origin point. Donor Ben Rau, who worked for Felsenthal, dated the object to 1942. The form of the maker's name indicates it was probably manufactured for the U.S. Army in the 1950s.

This protractor is very similar to 1977.1141.11, although the scale for plotting the distance of fired artillery is in yards rather than in meters.